Robotics is commonly used in the semiconductor manufacturing industry to transfer semiconductor wafers, also known as substrates, throughout the fabrication area. Wafer cassettes are typically used to retain a group of wafers. Many times throughout the manufacturing process, the individual semiconductor wafers may be loaded into or out of the wafer cassettes. Various robotic wafer transfer systems may be used. For example, the robotic wafer transfer systems typically utilize a wafer transfer blade that carries the individual wafers into and out of slots of the wafer cassette.